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Publication numberUS4565614 A
Publication typeGrant
Application numberUS 06/657,536
Publication dateJan 21, 1986
Filing dateOct 4, 1984
Priority dateOct 14, 1983
Fee statusPaid
Also published asCA1244572A1, DE3337397A1, EP0138140A1, EP0138140B1
Publication number06657536, 657536, US 4565614 A, US 4565614A, US-A-4565614, US4565614 A, US4565614A
InventorsHartmuth Buding, Zsolt Szentivanyi, Joachim Thormer
Original AssigneeBayer Aktiengesellschaft
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Polymer mixtures and co-vulcanizates produced therefrom
US 4565614 A
Abstract
Co-vulcanizates are produced from mixtures of (a) from 95 to 5% by weight of fluoroelastomers and (b) from 5 to 95% by weight of elastomers which contain nitrile groups and have from 25 to 140 nitrile-nitrogen atoms and less than 35 double bonds per 1000 carbon atoms, and (c) conventional mixture ingredients, the percentages relating to the sum total of (a) and (b). The co-vulcanizates are suitable for the production of seals and other rubber articles, in particular for areas of use which impose exacting requirements.
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Claims(5)
We claim:
1. Mixtures comprising (a) from 95 to 5% by weight of a fluoroelastomer and (b) from 5 to 95% by weight of an elastomer which contains nitrile groups and has from 25 to 140 nitrile-nitrogen atoms and less than 35 double bonds per 1000 carbon atoms, the percentages relating to the total of (a) and (b).
2. Mixtures according to claim 1 of from 70 to 10% by weight of (a) and from 30 to 90% by weight of (b).
3. Mixtures according to claim 1, in which (b) contains less than 12 double bonds per 1000 carbon atoms.
4. Mixtures according to claim 1, in which (b) contains less than 2 double bonds per 1000 carbon atoms.
5. Co-vulcanisates produced from the mixtures according to claim 1 by peroxidic cross-linking or by radiation cross-linking.
Description

This invention relates to vulcanisable polymer mixtures of fluoroelastomers and substantially saturated elastomers containing nitrile groups, and to the covulcanisates produced therefrom by peroxidic cross-linking.

Fluoroelastomers are special rubbers which are stable to heat and resistant to chemicals, steam and hot water, and which in particular exhibit only a slight swelling in hydrocarbons. They are produced by polymerising or copolymerising highly-fluorinated or perfluorinated monomers and they may be cross-linked by means of peroxides. Vulcanisates produced therefrom have an average strength.

Fluoroelastomers are described in, for example, German Offenlegungsschrift Nos. 1,655,010; 1,795,819 and 2,836,296 and in European Offenlegungsschrift Nos. 77 998, 48 308 and 99 079.

Substantially saturated elastomers which contain nitrile groups are obtained, for example, by hydrogenating nitrile rubbers (butadiene-acrylontrile copolymers). The vulcanisates produced therefrom are distinguished by a considerable strength.

Elastomers of this type are known, for example from U.S. Pat. No. 3,700,637 and German Offenlegungsschrift Nos. 2,539,132 and 2,913,992.

Surprisingly, it has now been found that it is possible to produce mixtures from fluoroelastomers and substantially saturated elastomers containing nitrile groups, which mixtures may be cross-linked peroxidically or by radiation to produce covulcanisates having outstanding properties.

Thus, the present invention provides mixtures of (a) from 95 to 5% by weight, preferably from 70 to 10% by weight of fluoroelastomers and (b) from 5 to 95% by weight, preferably from 30 to 90% by weight of elastomers which contain nitrile groups and have from 25 to 140 nitrile nitrogen atoms per 1000 carbon atoms and less than 35 double bonds, preferably less than 12 double bonds and in particular less than 2 double bonds, per 1000 carbon atoms, and (c) conventional mixture ingredients, the percentages relating to the sum total to the sum total of (a) and (b).

This invention also provides co-vulcanisates which are obtained from the above-mentioned mixtures by peroxidic cross-linking or radiation cross-linking.

The fluoroelastomers contain the following as monomers, for example: tetrafluoroethylene, vinylidene fluoride, tetrafluoropropene, pentafluoropropene, hexafluoropropene and perfluoromethyl-perfluorovinylether and optionally also non-fluorinated monomers, such as ethylene and propene, or small quantities of bromided or iodided olefines. The fluorine contents amount to from 50 to 71% by weight and the molar weights Mw are from 10,000 to 10,000,000.

The starting materials for the production of the substantially saturated elastomers containing nitrile groups are preferably nitrile rubbers and from 10 to 48% by weight of (meth)acrylonitrile from 50 to 85% by weight of a conjugated diene having from 4 to 9 carbon atoms and from 0 to 30% by weight of a third monomer, for example (meth)acrylic acid, (meth)acrylic acid alkylester or vinyl acetate which are hydrogenated, for example according to DE-OS No. 25 39 132.

The nitrile rubbers preferably consist of from 48 to 15% by weight of acrylonitrile and from 52 to 85% by weight of butadiene or isoprene.

Conventional ingredients of a rubber mixture are known to those skilled in the art. These are, for example fillers, plasticizers, anti-agers, processing auxiliaries, pigments, acid acceptors and vulcanisation chemicals, while peroxides are used for the vulcanisation of the rubber mixture according to the present invention.

Examples of suitable peroxides are the following:

dialkyl peroxides, ketal peroxides, aralkyl peroxides, peroxyethers and peroxyesters. The following are preferably used: di-tert.-butyl peroxide, bis-(tert.-butylperoxyisopropyl-benzene), dicumyl peroxide, 2,5-dimethyl-2,5-di(tert.-butylperoxy)-hexane, 2,5-dimethyl-2,5-di-(tert.-butylperoxy)-hexene-(3), 1,1-bis(tert.-butylperoxy)-3,3,5-trimethylcyclohexane, benzoylperoxide, tert.-butylcumylperoxide or tert.-butylperbenzoate.

The quantitites of peroxide are from 1 to 15% by weight, preferably from 2 to 4% by weight, based on the solid rubber.

Generators of high-energy electromagnetic rays are suitable as sources for the radiation cross-linking, such as X-rays and γ-rays, as well as generators of electron beams.

Surprisingly, the co-vulcanisates exhibit superadditive values for the strengths, see FIG. 1. They also exhibit a very slight swelling in liquid hydrocarbons (see FIG. 2) and an outstanding property spectrum in the other essential rubber properties. Therefore, they are suitable for the production of seals and other rubber articles, in particular in areas of use in which exacting requirements are imposed as regards strength, tear propagation resistance, swelling resistance and mould releasing ability, for example in the production and use of rubber articles for the exploration and extraction of crude oil, in particular in the off-shore field.

FIG. 1 shows the dependence of the strength F on the composition of the co-vulcanisate.

FIG. 2 shows the dependence of the swelling ΔG on the composition of the co-vulcanisate.

In FIG. 1, the strength F[MPa] is plotted against the composition, the values for % by weight of polymer, based on total polymer, being determined. The content of fluoroelastomer increases continuously from the left-hand side (0% by weight) to the right-hand side (100% by weight). The content of substantially saturated elastomers containing nitrile groups decreases accordingly. The dotted line represents the expected course obtained from the known strengths of pure elastomers, based on the respective mixture.

In FIG. 2, the swelling ΔG in % in ASTM fuel C at room temperature after seven days is plotted in a corresponding manner against the composition.

The elastomers tested for FIGS. 1 and 2 are those of Example 1.

EXAMPLE

The following base mixtures I and II were produced in a 1.3 liter laboratory kneader at 60 C. operating at 36 r.p.m. and under a stamping pressure of 8 bars.

______________________________________                Parts by weight______________________________________Mixture IHNBR*                  100Carbon black 550       20Carbon black 765       40Magnesium oxide        8Calcium oxide          3Distyryldiphenylamine  1Nickeldibutyldithiocarbamate                  1Triallylcyanurate (80% by weight)                    1.5Bis-(tert.-butylperoxyisopropyl-benzene)                    5.0(40% by weight)Mixture IIFKM**                  100Pyrogenic silica (130 m2 /g acc. to BET)                  20Calcium oxide          3Triallylcyanurate (80% by weight)                  1.3Bis-(tert.-butylperoxyisopropylbenzene)                  1.5(40% by weight)______________________________________ *Hydrogenated acrylonitrilebutadiene copolymer having a content of acrylontrile of 34% by weight, a degree of hydrogenation of 99% and a Mooney viscosity ML at 100 C. (1 + 4) of 75 **Fluorine rubber having a fluorine content of 64% by weight, a specific weight 1.81 g/cm3  and a Mooney viscosity ML at 121 C. (1 + 10) of 60.

Using the base mixtures I and II, blends were produced on a laboratory roller (φ150 mm, 24 r.p.m., 1.2 friction) at 40 C. then vulcanised at 170 C. for 20 minutes and annealed at 175 C. for 5 hours (standard rod 3a).

The following Table gives the results of the vulcanisates and co-vulcanisates.

______________________________________Mixture I (parts by weight)              100     60     30    --Mixture II (parts by weight)              --      40     70    100% by weight of HNBR, based on              100     51.2   23.1   0total rubber% by weight of FKM, based on               0      48.8   76.9  100total rubberF [MPa]            20.6    19.8   14.4  10.5D [%]              380     290    360   390M50 [MPa]     3.0      3.5    2.7  2.5M100 [MPa]    5.2      5.6    4.1  3.2HRT [Shore A]  75     77     74     72ΔO, Swelling in ASTM fuel O,               50     30     19    --RT, 7 days; [% by weight.][%]Tor max [C.] [%]              -13     -8     -6    -3______________________________________
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3700637 *May 8, 1970Oct 24, 1972Shell Oil CoDiene-nitrile rubbers
US4251432 *Mar 6, 1978Feb 17, 1981Trw Inc.Method of providing curable fluoroelastomer gums having coupling agent coated particulate carbonaceous fillers
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5260351 *Mar 17, 1993Nov 9, 1993E. I. Du Pont De Nemours And CompanyRadiation curing of perfluoroelastomers
US5473017 *Sep 14, 1994Dec 5, 1995Exxon Chemical Patents Inc.Intervulcanized elastomer blends
US5621044 *Jun 6, 1995Apr 15, 1997Exxon Chemicals Patents, Inc.Intervulcanized elastomer blends
US6610761 *Jun 1, 1999Aug 26, 2003Daikin Industries, Ltd.Molded rubber irradiated with ionizing radiation and process for producing the same
CN101186726BNov 20, 2007Aug 3, 2011广州机械科学研究院Rubber-plastic composite material and application thereof
EP0532714A1 *Jun 7, 1990Mar 24, 1993Du PontRadiation curing of perfluoroelastomers.
WO2007081213A1 *Oct 12, 2006Jul 19, 2007Fmc Kongsberg Subsea AsElastomer composition and method of manufacturing thereof
Classifications
U.S. Classification522/112, 525/194, 525/199, 525/192
International ClassificationC08L27/00, C08L57/00, C08L23/00, C08L15/00, C08L101/00, C08F2/46, C08L9/02, C08L27/12, C08L21/00, C08L7/00, C08L1/00
Cooperative ClassificationC08L15/005, C08L27/12, C08L15/00
European ClassificationC08L27/12, C08L15/00B
Legal Events
DateCodeEventDescription
Oct 4, 1984ASAssignment
Owner name: BAYER AKTIENGESELLSCHAFT LEVERKUSEN, GERMANY A COR
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:BUDING, HARTMUTH;SZENTIVANYI, ZSOLT;THORMER, JOACHIM;REEL/FRAME:004321/0431
Effective date: 19840917
Feb 23, 1989FPAYFee payment
Year of fee payment: 4
Jun 28, 1993FPAYFee payment
Year of fee payment: 8
Jul 21, 1997FPAYFee payment
Year of fee payment: 12